The control module judged the Reductant pressure signal implausible: it stayed inside electrical limits but did not match the value expected for the current operating conditions.
Symptoms
MIL or SCR/AdBlue warning illuminated
Possible start-count-down or torque limitation on some applications
Possible causes
Wiring
reductant pressure sensor
ECM
Recommended checks
Read NOx sensor values and dosing system status
Check reductant level and quality data
Inspect dosing valve, lines and heater operation
Check wiring and connectors of the SCR components
Check for OEM technical bulletins and software updates
Powertrain: engine, transmission and driveline systems.
2
Generic SAE-standard code: same meaning on every make.
04B
Specific fault index within the subsystem.
Frequently asked questions about P204B
What does P204B mean?
Reductant pressure sensor - circuit range/performance. The control module judged the Reductant pressure signal implausible: it stayed inside electrical limits but did not match the value expected for the current operating conditions.
Is P204B generic or manufacturer-specific?
P204B is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.
Can TuningBot remove P204B at file level?
If the fault logic lives in the ECU calibration, yes: our DTC Removal file service disables the specific fault entry and, where the ECU needs it, corrects the checksum too. Not sure whether your case qualifies? Request a free assessment and our engineers will check your ECU file.
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